This work is concerned with the development of new analytical methodology for biological and biomedical purposes. Much of the work involves gas phase analysis with analytical systems based on mass spectrometry. A novel type of mass spectrometer has been developed in which the ionization process occurs at atmospheric pressure. The instrument detects positive and negative ions, and has shown subpicogram sensitivity of detection. The current studies are on negative ion formation, and the results indicate that negative ion mass spectrometry may prove to be very useful in analytical work. These ions are formed by electron capture, by proton removal and by reaction with 02. Work in amino acids and peptides has continued with the development of additional methods for characterizing peptides by mass spectrometry. Studies of prostaglandins resulted in the discovery of a new series of metabolites - the 19-hydroxy prostaglandins. Studies in computer science were continued with the development of new interactive programs for the analysis of mass spectral data. Current analytical systems based on a combination of a gas chromatograph, a mass spectrometer and a computer can be provided with greatly increased analytical capabilities by the use of interactive data analysis programs.